Norm / Mike. Take a look at this idea. Our main issue is the desire for the magnet toflip over. as this creates two problems. 1) the sides of the magnet will want to rub creating friction, 2) it will want to flip (front to back). If we put roller balls on the sides yes it will create a friction but not that great ? Front to back is still a problem but if the front and back were lead lined would this stop it ?

The obvious issue is the light blue mag being pushed up and out of the channel.

NOTE most of this is burried in the ground.